Fence top rail



FIG. 1 is a front perspective view of a fence top rail, showing my new design;

FIG. 2 is a left side elevation view, the right side elevation view being identical thereto;

FIG. 3 is a front elevation view of a fence top rail;

FIG. 4 is a top plan view of a fence top rail; and,

FIG. 5 is a bottom plan view of a fence top rail.

The broken lines are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a fence top rail, as shown and described. 